Mayr, Ulrich
Kuhns, David
2014-10-17T16:12:43Z
2014-10-17
http://hdl.handle.net/1794/18500
Cognitive control refers to the brain's ability to control attention and other cognitive functions in the service of intention-driven behaviors; moreover, it is an essential aspect in cognition. Cognitive control is commonly evaluated through the so-called conflict adaptation effect, which is revealed through trial-to-trial changes in performance after experiencing cognitive conflict. The conflict monitoring theory is a prominent theory intended to describe conflict adaptation and explain how cognitive control might be engaged in the face of conflict. A passive carryover account, originally aimed at explaining task switching and based on parallel distributed processing models, may represent a superior alternative to the conflict monitoring account. In the carryover account, passive inertia of the cognitive control state explains the trial-to-trial modulation of conflict effects. One problem with conflict adaptation is that the typical paradigms used to create conflict adaptation often include trial-to-trial repetitions that mimic the same performance pattern through priming. Conflict monitoring theory also has difficulty explaining other issues such as whether conflict adaptation is task-specific. A meta-analysis of the so-called conflict adaptation effect suggests trial-to-trial repetitions do not entirely account for conflict adaptation effects, but these effects do appear to be task-specific. The meta-analysis also suggests the withdrawal of control is episodic rather than temporal and conflict adaptation may be sensitive to experimental session length. A novel eye-tracking paradigm addresses the timing of control engagement. The results suggest dynamic regulation of attention coupled with conflict detection. This more tightly coupled detection and regulation process in the context of conflict adaptation is more consistent with a carryover account than what would be expected from the conflict monitoring theory. A subsequent eye-tracking paradigm further supported that trial-to-trial modulations of control are generally more consistent with a carryover account than they are with the conflict monitoring theory. Overall, the empirical evidence points toward a carryover model of cognitive control.
en_US
University of Oregon
All Rights Reserved.
Attention
Cognitive Control
Cognitive Model
Conflict Adaptation
Eye-tracking
Conflict and Control: How Does the Brain Regulate Cognitive Control in the Presence of Conflict?
Electronic Thesis or Dissertation
2016-10-17
Ph.D.
doctoral
Department of Psychology
University of Oregon

Drew, Trafton, 1980-
2010-02-17T01:58:11Z
2010-02-17T01:58:11Z
2009-06
http://hdl.handle.net/1794/10198
xiii, 155 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
In the multiple object tracking (MOT) task, observers are presented with multiple identical objects, some of which are temporarily identified as targets. After a selection period, all objects move randomly and independently for several seconds. At the end the motion period, all objects stop and observers must identify the target objects again. This task has been used to study a variety of important cognitive questions from object-based attention to cognitive development, divided attention and the development of expertise. Yet, surprisingly little is known about the neural mechanisms that underlie the ability to track multiple targets independently. Although a number of researchers have used fMRI (functional magnetic imaging) to examine what areas are active during MOT, the current set of studies is the first to employ ERPs (event-related potentials) to examine the neural mechanisms of MOT. With excellent temporal resolution, the ERP methodology allows researchers to delineate the time course of different phases of a single task with millisecond precision, something not possible with fMRI. In Chapter II, we manipulated the number of targets and difficulty of tracking and observed a lateralized contralateral negativity that was sensitive to the number of targets but not difficulty of tracking. Chapter III examined the effect of irrelevant white probes flashed briefly throughout the trial while observers tracked. We observed modulations of early visual components that indicated that during tracking, spatial attention focused on targets but did not differentiate between distractors and empty space. Finally, in Chapter IV, we examined the relationship between visual working memory (VWM) and MOT by manipulating the presence or absence of task relevant motion. We found that the waveforms evoked by an MOT task in the absence of task-relevant motion were nearly identical to waveforms evoked by the VWM task, suggesting that VWM is an important part of the typical MOT task. This thesis includes previously published and unpublished material.
Committee in Charge: Edward Vogel, Chairperson, Psychology;
Edward Awh, Member, Psychology;
Ulrich Mayr, Member, Psychology;
Paul van Donkelaar, Outside Member, Human Physiology
en_US
University of Oregon
University of Oregon theses, Dept. of Psychology, Ph. D., 2009;
Attention
Working memory
Tracking
Individual differences
Cognitive psychology
Electrophysiological measures of attentional tracking and working memory
Thesis

McCollough, Andrew Willis, 1974-
2011-09-09T01:11:21Z
2011-09-09T01:11:21Z
2011-06
http://hdl.handle.net/1794/11555
xiii, 143 p. : ill. (some col.)
The cognitive ability to group information into chunks is a well known phenomenon, however, the effects of chunking on visual representations is not well understood. Here we investigate the effects of visual chunking using Gestalt grouping principles in two tasks: visual working memory change detection and multiple object tracking. Though both these tasks have been used to study cognitive functions in the past, including object-based attention, attentional control and working memory capacity, the effect of grouping on mental representations in these tasks has not been well characterized. That is, while researches have measured effects of grouping on behavioral output in similar tasks, there are few studies of the effects of grouping on neurophysiological indices of object representations. Indeed, these current studies are the first to use event-related potentials (ERPs) to elucidate the effect of grouping on active mental representations of visual stimuli. In the visual working memory task, observers remembered either the color or orientation of pacman stimuli across a delay. We manipulated the collinearity of these objects, whether or not they formed a Kanizsa triangle figure, and measured the behavioral and electrophysiological effects. In the multiple object tracking task, a subset of identical stimuli were briefly cued as targets and then their motion was tracked by participants. We manipulated whether and which Gestalt heuristics were used to bind targets together during their motion and measured the effects on behavior and electrophysiology. In both tasks we compared the grouped to ungrouped conditions. We found that across experiments and tasks behavioral performance was enhanced in grouping conditions compared to ungrouped conditions. Furthermore, the waveforms evoked by grouped stimuli were reduced compared to waveforms produced in response to locally identical but ungrouped stimuli. These data suggest that the mental representation of visual objects may be reshaped moment-by-moment by grouping cues or task demand, giving rise to a flexible, active and dynamic yet parsimonious representation of the visual world.
Committee in charge: Edward K. Vogel, Chair;
Edward Awh, Member;
Ulrich Mayr, Member;
Paul van Donkelaar, Outside Member
en_US
University of Oregon
University of Oregon theses, Dept. of Psychology, Ph. D., 2011;
Psychology
Neurosciences
Attention
Electrophysiology
ERP
Gestalt
Kanizsa
Visual Working Memory
The Influence of Gestalt Grouping Principles on Active Visual Representations: Neurophysiological Evidence
Thesis